Combined take-up and safety lock



Aug. 29, 1933 E. v. FRANCIS El AL COMBINED TAKE-UP AND SAFETY LOCK Filed Feb. 14, 1930 2.Sheets-Sheet l .m W Z m MFA rW m a m Aug. 29, 1933- E. v. FRANCIS ET AL COMBINED TAKE-UP AND SAFETY LOCK Filed Feb. I4 1930 2 Sheets-Sheet 2 i 0 w Wm r m m m 2 A Z 7 q w 2 Z 4% o 6.0 3 Cm/ W Z fl 4 n0 0 m Mwf m 7 a q M 9 6 9" E h m. 4 m W6). 5 Z "o 1 w Patented Aug. 29, 1933 UNITED STATES PATENT oer-ice Earle V. Francis and Alexis W. Lemmon, Columbus, Ohio, assignors to The Jeffrey Manufacturing Company, Columbus, Ohio, a corporation of Ohio Application February 14, 1930. Serial No. 428,379

, 6 Claims.

This invention relates to a combined take-up and safety lock for shafts of endless conveyors. An important object of the invention is to provide means for taking up slack in an endless conveyor element which has associated therewith a back stop or safety lock for preventing accidental reverse movement of the conveyor element and to provide an arrangement whereby adjustment of the conveyor to take up slack does not interfere with the operation of the back stop and the back stop does not interfere with the adjustment of the conveyor.

Another important object of the invention is to provide a back stop on each end of the conveyor shaft to prevent reverse rotation thereof, so as to overcome the imposition of unequal stresses upon the parts and to connect the back stops in a manner to equalize the stresses imshaft.

Another object of the invention is to provide the back stops with yielding abutments which are connected for relieving the conveyor parts from r excessive shocks when stopped with a load imposed thereon.

A further object of the invention is to provide means for automatically closing the openings in the conveyor housing about both ends of the shaft when the latter is adjusted so that the housing will effectively exclude deleterious matter and will confine the material being handled.

A still further object of the invention is to provide simple and efiicient means for adjustably mounting both ends of a conveyor shaft and a common operating means for effecting their simultaneous adjustment.

Other objects and advantages of the invention will become apparent during the course of the following description.

In the accompanying drawings forming a part of the description and wherein like numerals are employed to designate like parts throughout the several views,

Figure 1 is a side elevation of the head end of an elevator illustrating the invention applied thereto.

Figure 2 is a vertical section of the same, taken on the line 2-2 of Figure 1.

Figure 3 is an elevation of the back of a portion of the elevator housing looking from the left of Fig. 1.

Figure 4 is an enlarged horizontal section taken on the line 4i of Figure 1, and

Figure 5 is an enlarged detail sectional View of the closure plate guide on line 5 5 of Figure 1.

(c1. res-227) As one example of the invention, it has here been illustrated in conjunction with an endless bucket elevator, but it is to be understood that the invention is not confined to this particular use and it may be effectively used in other fields. A vertical elevator housing or support 5 is provided to enclose a bucket elevator including a head shaft 6, especially when light and fluffy material is being handled and is equipped with a discharge spout 7, communicating with the housing at the point where the buckets of the elevator discharge centrifugally, to receive and convey the discharged material to a point of storage or further handling. The head shaft 6 within the housing has keyed thereto a pair of spaced sprocket wheels 8 over which are trained the spaced endless chains 9 of the endless conveyor elements, which have connected thereto in any well known manner, elevator buckets 10. The endless chains 9 are, of course, trained about similar sprockets secured to a foot shaft, not shown, disposed at the lower end of the elevator housing 5 and motive power to the conveyor is transmitted through the shaft 6, which may have 7 associated with one end 11 thereof any desired 8 form of power transmission element, not shown; or the head shaft may, if desired, be a prime mover shaft such as the armature shaft of an electric motor mounted in any suitable manner.

From Figure 2 it will be seen that opposite ends of the head shaft 6 project out through openings 12 in opposite sides of the elevator housing and are journalled in sectional bearings 13 fastened to the lower horizontal bar 14 of a vertically movable bearing frame indicated in its entiretyby the numeral 15. Each bearing frameis composed of a pair of vertical horizontally spaced grooved side bars 16, each of which consists of a pair of oppositely facing spaced angle bars 17 with a filler strip 18' disposed therebe- 9 tween to retain the adjacent faces ofv the angle bars in spaced relation to provide a groove 19 in the longitudinal outer edge of the side bar to embrace guides of a guide frame 20 secured in fixed relation to the elevator housing as will be more fully described hereinafter. ihe lower horizontal bar 14 of each bearing frame is composed of a pair of oppositely facing angle bars 21 which have their horizontal flanges 22 arranged in the same plane to form a support to which the bearings 13 are bolted by the bolts 23. These angle bars 21 are secured at their ends to the vertical angle bars 17 by means of angle cleats 24.

Each bearing frame has its transverse top rail 1' composed of a pair of horizontally spaced channel bars 25 held in spaced relation to each other and secured to the vertical angle bars 17 by means of upper and lower angle cleats 26 and 2'7, respectively. Thus it will be seen that each bearing frame comprises generally a substantially rectangular frame.

These bearing frames 15 are mounted for vertical adjustment in a substantially rectangular guide frame indicated in its entirety by the numeral 20 and has its two vertical legs and its lower horizontal portion formed T-shape in cross section as best appreciated from Figure 4, so that the stems of the vertical legs will be disposed in the grooves 19 of the bearing frame to slidably mount the same. This guide frame 20 is composed of a pair of sections bolted together along vertical lines 28 and rests upon horizontal beams 29 secured to the elevator housing. Each of these beams 29 consists of a pair of oppositely facing angle braces 30 juxtaposed with their horizontal flanges arranged in a horizontal plane for the stable support of the base of the guide frame to which they are bolted as best seen in Figure 2. The tops of the guide frames 20 are secured in fixed relation to opposite sides of the elevator housing by means of a pair of horizontal transverse channel beams 30 which rest upon the top of the elevator housing and are secured at opposite ends to the upper portions of the guide frames 20.

. The top cross bar 31 of each guide frame 20 is sectional as hereinbefore stated and joined along the line 28 at which point a vertical bearing 32 with anti-friction means is provided for the support of a nut 33 having a depending sleeve extension 34 which extends through the bearing 32 for mounting. About the upper hub of each nut is fixedly attached a horizontally disposed worm wheel 35. A screw shaft 36 extends through the nut 33 at its upper end and its lower end is equipped with an eyelet disposed between the channel bars 25 of the vertically adjustable bearing frame to be pivotally connected thereto on a horizontal axis by means of a pin 3'7. Rotation of the nut 33 will effect vertical movement of the screw shaft 36 and consequently the bearing frame 20. Since one of these bearing frames and adjusting mechanisms is provided on each side of the elevator housing for the two ends of the head shaft 6, it is desirable to provide means for simultaneously adjusting the bearing frames to the same degree simultaneously and for this purpose common operating means in the form of a horizontally disposed shaft 38 is mounted in bearings 39 fixed to the tops of the guide frames 20 on opposite sides of the housing. This shaft 38 is equipped at each end with a worm 40 for mesh with the worm wheels 35 and a hand wheel 41 is fixed to the shaft 38 for rotating it in either direction to cause simultaneous rotation of the nuts 33 to effect simultaneous movement of the two bearing frames 15.

Due to the fact that the head shaft 6 is vertically adjustable in the elevator housing, necessarily the openings 12 in opposite'sides thereof must be of sufiicient size to permit of vertical movements of the head shaft. Now, in order to keep the openings 12 of the housing closed regardless of the position of the shaft 6 with respect thereto, to exclude deleterious material from the elevator housing and to confine material being handled therein when its nature is such as to possess tendencies to escape during agitation caused by loading and unloading from the bucket elevator, rectangular closure plates 42 are movable with the head shaft 6 and overlap the edges of the openings 12 in all positions of adjustment of the head shaft. One of such closure plates 42 is provided for each end of the shaft 11 where it extends through the casing 5 and in this instance is provided with a circular aperture to closely embrace an annular flange 44 of a back stop device to be presently described. As best seen in Figures 2 and 5, each plate 42 has its vertical edges 60 slidably mounted in vertical guideways 61 provided on the casing 5. The closure plates 42 are held in proper position by braces 42' secured thereto and to the horizontal top rails 25 of the bearing frame 15. As is evident in Figure 2, the upper and lower flanged edges of each plate 42 overlap the upper and lower edges of the openings 12 in all positions of adjustment of the closure plates. From the foregoing description it will be evident that the head shaft 6 can be vertically adjusted to take up slack in the bucket elevator chains 9 by reason of the bearings 18 on the shaft being movable with the bearing frames 15 along the guides constituted by the vertical legs of the guide frame 20.

As is well understood in this art, a bucket elevator will reverse its rotation when the motive power is cut off and the buckets are loaded due to the loaded condition of the buckets along one run of the elevator and the empty condition of those along the opposite run, unless a check of some kind is provided to prevent such reverse rotation tendencies. If no check is provided the reverse movement of the elevator will attain great impetus due to the loaded condition of the buckets on one side and will cause them to move backwardly of their intended movement to prematurely discharge their contents back at the loading point to say nothing of the damage inflicted upon the elevator incident to its accidental reverse movement. Accordingly, provision has been made for a check or back stop to prevent such reverse rotation of the elevator which is of a character to faithfully perform its functions as well as to permit of the vertical adjustment of the elevator shaft to take up slack in the elevator chains. A check or back stop is provided for each end of the head shaft 6 and as they are identical, a description of one will suflice for both. Each of these back stops includes a circular plate 43 secured to the outer face of each sprocket 8. This plate 43 is equipped with an annular flange 44, the outer margin of which is angularly disposed as at 45 to be arranged in spaced parallel relationship with the main body of the plate. Between the flange 45 and the plate 43 a plurality of gravity actuated pawls 46 are pivotally mounted for cooperation with a ratchet wheel 4'? loosely mounted upon the head shaft 6 between the sprocket 8 and the bearing 13 as best seen in Figure 2. It will be noted from Figure 1 that a Vernier relationship exists between the arrangement of the pawls 46 and the teeth of to stop reverse rotation of the 'head shaft. In order to constitute an abutment for this purpose the ratchet plate 47 is provided with an extended arm 49 which extends between the guide frame 20 and the housing 5 and through a vertical slot 50 in a brace 51 secured to the housing. The outer end of each arm 49 is connected to the lower end of a coiled tension spring 52, the upper end of which is connected by a vertically adjustable eyelet 53 to the end of an equalizing bar 54. This equalizing bar is suspended between its ends by an eyelet 55 adjustable with respect thereto and connected to an eye bolt 56, depending from an angle bar 5'7 secured to the elevator housing as shown. Thus, it will be seen that a yielding abutment is provided for each back stop and that they are connected to equalize the stresses imposed upon the parts when the back stops act to prevent reverse rotation of the elevator mechanism. Excessive movements of the arms 49 constituting parts of the yieldable abutments are stopped, by their engagement with opposite ends of the slots 50. Due to this particular anchorage of the abutments for the back stops, it will be obvious that no interference is offered thereby against vertical adjustments of the head shaft carrying the back stop mechanism, and, moreover, the yielding abutments through the adjustment of the eye bolts 53 and 55 can be made to compensate for the adjustments of the head shaft, should such be required. During normal operations of the bucket elevator, the pawls 46 will be swung by centrifugal force clear of the teeth of the ratchet wheels 4'7 and into engagement with the overhanging flange 44 to ride thereon and insure quiet operation, but whenever motive power to the bucket elevator is turned off with the buckets loaded, the elevator will tend to move in a reverse direction and one of the pawls 46 of each back stop will immediately engage one of the teeth of the ratchet wheels 4'7, causing the arms 49 to tension the springs 52 to absorb the shocks incident to stopping reverse movement of the bucket elevator. Preferably, the teeth of the wheels 47 and the relative positions of the pawls 46 with respect thereto on opposite ends of the shaft is the same, so that both back stops are effective simultaneously to prethe arrangement, size and shape of the parts may be resorted to without departing from the spirit of the invention or the scope of the appended claims.

What we claim is:

1. The combination with an elevator mechanism including a support having a slot, a head shaft, a back stop device for preventing reverse rotation of said shaft and including an abutment arm extending through said slot and adapted for engagement with one end thereof to limit movement of said arm, and resilient means normally retaining said arm spaced from the'end of said slot.

2. The combination with an elevator mechanism comprising a shaft, a plurality of back stop devices associated therewith and including yielding abutments to prevent reverse rotation of said shaft; of means for equalizing the strains imposed upon said abutments.

3. The combination with an elevator mechanism comprising a shaft, a plurality of back stop devices associated therewith and including yielding abutments to prevent reverse rotation of said shaft; of means connecting said abutments for equalizing strains imposed thereon.

4. The combination with an elevator mechanism comprising a shaft, a plurality of back stop devices associated therewith and including yielding abutments to prevent reverse rotation of said shaft; of a member extending from one abutment to the other and connected thereto to equalize strains imposed upon said abutments.

5. The combination with an elevator mechanism comprising a head shaft, a plurality of back stop devices associated therewith and including abutments to prevent reverse rotation of said shaft, a bar supported from the elevator mechanism, and resilient means connecting said bar and abutments.

6. The combination with an elevator mechanism comprising a head shaft, a plurality of back stop devices associated therewith and including abutments to prevent reverse rotation of said shaft, a bar suspended between its ends, and resilient means connecting the ends of said bar with said abutments.

EARLE V. FRANCIS. ALEXIS W. LEMMON. 

